Why do so many of today's mathematicians present their work in such a
formal way, hiding their ideas behind all sorts of notation,
definitions and the like? Why is there so little explanation of the
ideas and concepts? I like math, but I find this aspect of it very
annoying.

This is a math history question. Is it true that Socrates is believed to
have been imprisoned for teaching the existence of pi? I understand that
the belief in, or the teaching of, the existence of pi was considered
heresy in his day.

If the base of an isosceles triangle is 4, and the height is 5, then the
sides are equal to the square root of 21. How can this triangle exist
(except in theory) if you can never measure or draw the square root of
21?

What did Euler wrongly assume when he first derived pi^2/6 from the infinite sum of 1/n^2? Doctor Jordan reveals two missteps initially committed by the famous mathematician on this now-classic result.